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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2014 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: SnapshotKVTransaction.html 939 2015-05-29 01:16:17Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.jsimpledb.kv.mvcc;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import java.io.Closeable;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import java.util.concurrent.atomic.AtomicLong;<a name="line.11"></a>
<span class="sourceLineNo">012</span><a name="line.12"></a>
<span class="sourceLineNo">013</span>import org.jsimpledb.kv.KVStore;<a name="line.13"></a>
<span class="sourceLineNo">014</span>import org.jsimpledb.kv.KVTransaction;<a name="line.14"></a>
<span class="sourceLineNo">015</span>import org.jsimpledb.kv.StaleTransactionException;<a name="line.15"></a>
<span class="sourceLineNo">016</span>import org.jsimpledb.kv.TransactionTimeoutException;<a name="line.16"></a>
<span class="sourceLineNo">017</span>import org.jsimpledb.kv.util.ForwardingKVStore;<a name="line.17"></a>
<span class="sourceLineNo">018</span>import org.slf4j.Logger;<a name="line.18"></a>
<span class="sourceLineNo">019</span>import org.slf4j.LoggerFactory;<a name="line.19"></a>
<span class="sourceLineNo">020</span><a name="line.20"></a>
<span class="sourceLineNo">021</span>/**<a name="line.21"></a>
<span class="sourceLineNo">022</span> * {@link SnapshotKVDatabase} transaction.<a name="line.22"></a>
<span class="sourceLineNo">023</span> */<a name="line.23"></a>
<span class="sourceLineNo">024</span>public class SnapshotKVTransaction extends ForwardingKVStore implements KVTransaction, Closeable {<a name="line.24"></a>
<span class="sourceLineNo">025</span><a name="line.25"></a>
<span class="sourceLineNo">026</span>// Note: locking order: (1) SnapshotKVTransaction, (2) SnapshotKVDatabase<a name="line.26"></a>
<span class="sourceLineNo">027</span><a name="line.27"></a>
<span class="sourceLineNo">028</span>    private static final AtomicLong COUNTER = new AtomicLong();<a name="line.28"></a>
<span class="sourceLineNo">029</span><a name="line.29"></a>
<span class="sourceLineNo">030</span>    private final Logger log = LoggerFactory.getLogger(this.getClass());<a name="line.30"></a>
<span class="sourceLineNo">031</span>    private final long uniqueId = COUNTER.incrementAndGet();<a name="line.31"></a>
<span class="sourceLineNo">032</span>    private final long startTime;<a name="line.32"></a>
<span class="sourceLineNo">033</span>    private final SnapshotKVDatabase kvdb;<a name="line.33"></a>
<span class="sourceLineNo">034</span>    private final SnapshotVersion versionInfo;<a name="line.34"></a>
<span class="sourceLineNo">035</span>    private final MutableView mutableView;<a name="line.35"></a>
<span class="sourceLineNo">036</span><a name="line.36"></a>
<span class="sourceLineNo">037</span>    private boolean closed;<a name="line.37"></a>
<span class="sourceLineNo">038</span>    private long timeout;<a name="line.38"></a>
<span class="sourceLineNo">039</span><a name="line.39"></a>
<span class="sourceLineNo">040</span>    /**<a name="line.40"></a>
<span class="sourceLineNo">041</span>     * Constructor.<a name="line.41"></a>
<span class="sourceLineNo">042</span>     *<a name="line.42"></a>
<span class="sourceLineNo">043</span>     * @param kvdb the associated database<a name="line.43"></a>
<span class="sourceLineNo">044</span>     * @param versionInfo the associated MVCC version<a name="line.44"></a>
<span class="sourceLineNo">045</span>     */<a name="line.45"></a>
<span class="sourceLineNo">046</span>    protected SnapshotKVTransaction(SnapshotKVDatabase kvdb, SnapshotVersion versionInfo) {<a name="line.46"></a>
<span class="sourceLineNo">047</span>        this.kvdb = kvdb;<a name="line.47"></a>
<span class="sourceLineNo">048</span>        this.versionInfo = versionInfo;<a name="line.48"></a>
<span class="sourceLineNo">049</span>        this.startTime = System.nanoTime();<a name="line.49"></a>
<span class="sourceLineNo">050</span>        this.mutableView = new MutableView(versionInfo.getSnapshot());<a name="line.50"></a>
<span class="sourceLineNo">051</span>    }<a name="line.51"></a>
<span class="sourceLineNo">052</span><a name="line.52"></a>
<span class="sourceLineNo">053</span>// Accessors<a name="line.53"></a>
<span class="sourceLineNo">054</span><a name="line.54"></a>
<span class="sourceLineNo">055</span>    /**<a name="line.55"></a>
<span class="sourceLineNo">056</span>     * Get the {@link MutableView} associated with this instance.<a name="line.56"></a>
<span class="sourceLineNo">057</span>     *<a name="line.57"></a>
<span class="sourceLineNo">058</span>     * @return associated access and mutation state<a name="line.58"></a>
<span class="sourceLineNo">059</span>     */<a name="line.59"></a>
<span class="sourceLineNo">060</span>    public MutableView getMutableView() {<a name="line.60"></a>
<span class="sourceLineNo">061</span>        return this.mutableView;<a name="line.61"></a>
<span class="sourceLineNo">062</span>    }<a name="line.62"></a>
<span class="sourceLineNo">063</span><a name="line.63"></a>
<span class="sourceLineNo">064</span>    /**<a name="line.64"></a>
<span class="sourceLineNo">065</span>     * Get the MVCC version associated with this instance.<a name="line.65"></a>
<span class="sourceLineNo">066</span>     *<a name="line.66"></a>
<span class="sourceLineNo">067</span>     * @return associated MVCC version<a name="line.67"></a>
<span class="sourceLineNo">068</span>     */<a name="line.68"></a>
<span class="sourceLineNo">069</span>    public SnapshotVersion getSnapshotVersion() {<a name="line.69"></a>
<span class="sourceLineNo">070</span>        return this.versionInfo;<a name="line.70"></a>
<span class="sourceLineNo">071</span>    }<a name="line.71"></a>
<span class="sourceLineNo">072</span><a name="line.72"></a>
<span class="sourceLineNo">073</span>// ForwardingKVStore<a name="line.73"></a>
<span class="sourceLineNo">074</span><a name="line.74"></a>
<span class="sourceLineNo">075</span>    /**<a name="line.75"></a>
<span class="sourceLineNo">076</span>     * Get the underlying {@link KVStore}.<a name="line.76"></a>
<span class="sourceLineNo">077</span>     *<a name="line.77"></a>
<span class="sourceLineNo">078</span>     * &lt;p&gt;<a name="line.78"></a>
<span class="sourceLineNo">079</span>     * The implementation in {@link SnapshotKVTransaction} returns the {@link MutableView} associated with this instance.<a name="line.79"></a>
<span class="sourceLineNo">080</span>     *<a name="line.80"></a>
<span class="sourceLineNo">081</span>     * @return the underlying {@link KVStore}<a name="line.81"></a>
<span class="sourceLineNo">082</span>     */<a name="line.82"></a>
<span class="sourceLineNo">083</span>    @Override<a name="line.83"></a>
<span class="sourceLineNo">084</span>    protected KVStore delegate() {<a name="line.84"></a>
<span class="sourceLineNo">085</span>        this.checkState();<a name="line.85"></a>
<span class="sourceLineNo">086</span>        return this.mutableView;<a name="line.86"></a>
<span class="sourceLineNo">087</span>    }<a name="line.87"></a>
<span class="sourceLineNo">088</span><a name="line.88"></a>
<span class="sourceLineNo">089</span>// KVTransaction<a name="line.89"></a>
<span class="sourceLineNo">090</span><a name="line.90"></a>
<span class="sourceLineNo">091</span>    @Override<a name="line.91"></a>
<span class="sourceLineNo">092</span>    public SnapshotKVDatabase getKVDatabase() {<a name="line.92"></a>
<span class="sourceLineNo">093</span>        return this.kvdb;<a name="line.93"></a>
<span class="sourceLineNo">094</span>    }<a name="line.94"></a>
<span class="sourceLineNo">095</span><a name="line.95"></a>
<span class="sourceLineNo">096</span>    /**<a name="line.96"></a>
<span class="sourceLineNo">097</span>     * Set the transaction timeout.<a name="line.97"></a>
<span class="sourceLineNo">098</span>     *<a name="line.98"></a>
<span class="sourceLineNo">099</span>     * &lt;p&gt;<a name="line.99"></a>
<span class="sourceLineNo">100</span>     * {@link SnapshotKVTransaction}s do not perform any locking while the transaction is open. Therefore, the configured<a name="line.100"></a>
<span class="sourceLineNo">101</span>     * value is used instead as a timeout on the overall transaction duration. If the transaction is kept open for longer<a name="line.101"></a>
<span class="sourceLineNo">102</span>     * than {@code timeout} milliseconds, a {@link TransactionTimeoutException} will be thrown.<a name="line.102"></a>
<span class="sourceLineNo">103</span>     * &lt;/p&gt;<a name="line.103"></a>
<span class="sourceLineNo">104</span>     *<a name="line.104"></a>
<span class="sourceLineNo">105</span>     * @param timeout transaction timeout in milliseconds, or zero for unlimited<a name="line.105"></a>
<span class="sourceLineNo">106</span>     * @throws IllegalArgumentException if {@code timeout} is negative<a name="line.106"></a>
<span class="sourceLineNo">107</span>     */<a name="line.107"></a>
<span class="sourceLineNo">108</span>    @Override<a name="line.108"></a>
<span class="sourceLineNo">109</span>    public synchronized void setTimeout(long timeout) {<a name="line.109"></a>
<span class="sourceLineNo">110</span>        if (timeout &lt; 0)<a name="line.110"></a>
<span class="sourceLineNo">111</span>            throw new IllegalArgumentException("timeout &lt; 0");<a name="line.111"></a>
<span class="sourceLineNo">112</span>        this.timeout = timeout;<a name="line.112"></a>
<span class="sourceLineNo">113</span>    }<a name="line.113"></a>
<span class="sourceLineNo">114</span><a name="line.114"></a>
<span class="sourceLineNo">115</span>    @Override<a name="line.115"></a>
<span class="sourceLineNo">116</span>    public synchronized void commit() {<a name="line.116"></a>
<span class="sourceLineNo">117</span>        this.checkState();<a name="line.117"></a>
<span class="sourceLineNo">118</span>        this.closed = true;<a name="line.118"></a>
<span class="sourceLineNo">119</span>        this.kvdb.commit(this);<a name="line.119"></a>
<span class="sourceLineNo">120</span>    }<a name="line.120"></a>
<span class="sourceLineNo">121</span><a name="line.121"></a>
<span class="sourceLineNo">122</span>    @Override<a name="line.122"></a>
<span class="sourceLineNo">123</span>    public synchronized void rollback() {<a name="line.123"></a>
<span class="sourceLineNo">124</span>        if (this.closed)<a name="line.124"></a>
<span class="sourceLineNo">125</span>            return;<a name="line.125"></a>
<span class="sourceLineNo">126</span>        this.closed = true;<a name="line.126"></a>
<span class="sourceLineNo">127</span>        this.kvdb.rollback(this);<a name="line.127"></a>
<span class="sourceLineNo">128</span>    }<a name="line.128"></a>
<span class="sourceLineNo">129</span><a name="line.129"></a>
<span class="sourceLineNo">130</span>// Closeable<a name="line.130"></a>
<span class="sourceLineNo">131</span><a name="line.131"></a>
<span class="sourceLineNo">132</span>    /**<a name="line.132"></a>
<span class="sourceLineNo">133</span>     * Close this instance.<a name="line.133"></a>
<span class="sourceLineNo">134</span>     *<a name="line.134"></a>
<span class="sourceLineNo">135</span>     * &lt;p&gt;<a name="line.135"></a>
<span class="sourceLineNo">136</span>     * Equivalent to invoking {@link #rollback}.<a name="line.136"></a>
<span class="sourceLineNo">137</span>     */<a name="line.137"></a>
<span class="sourceLineNo">138</span>    @Override<a name="line.138"></a>
<span class="sourceLineNo">139</span>    public void close() {<a name="line.139"></a>
<span class="sourceLineNo">140</span>        this.rollback();<a name="line.140"></a>
<span class="sourceLineNo">141</span>    }<a name="line.141"></a>
<span class="sourceLineNo">142</span><a name="line.142"></a>
<span class="sourceLineNo">143</span>// Object<a name="line.143"></a>
<span class="sourceLineNo">144</span><a name="line.144"></a>
<span class="sourceLineNo">145</span>    @Override<a name="line.145"></a>
<span class="sourceLineNo">146</span>    public String toString() {<a name="line.146"></a>
<span class="sourceLineNo">147</span>        return this.getClass().getSimpleName()<a name="line.147"></a>
<span class="sourceLineNo">148</span>          + "[id=" + this.uniqueId<a name="line.148"></a>
<span class="sourceLineNo">149</span>          + ",vers=" + this.versionInfo.getVersion()<a name="line.149"></a>
<span class="sourceLineNo">150</span>          + (this.closed ? ",closed" : "")<a name="line.150"></a>
<span class="sourceLineNo">151</span>          + "]";<a name="line.151"></a>
<span class="sourceLineNo">152</span>    }<a name="line.152"></a>
<span class="sourceLineNo">153</span><a name="line.153"></a>
<span class="sourceLineNo">154</span>    @Override<a name="line.154"></a>
<span class="sourceLineNo">155</span>    protected void finalize() throws Throwable {<a name="line.155"></a>
<span class="sourceLineNo">156</span>        try {<a name="line.156"></a>
<span class="sourceLineNo">157</span>            if (!this.closed)<a name="line.157"></a>
<span class="sourceLineNo">158</span>               this.log.warn(this + " leaked without commit() or rollback()");<a name="line.158"></a>
<span class="sourceLineNo">159</span>            this.close();<a name="line.159"></a>
<span class="sourceLineNo">160</span>        } finally {<a name="line.160"></a>
<span class="sourceLineNo">161</span>            super.finalize();<a name="line.161"></a>
<span class="sourceLineNo">162</span>        }<a name="line.162"></a>
<span class="sourceLineNo">163</span>    }<a name="line.163"></a>
<span class="sourceLineNo">164</span><a name="line.164"></a>
<span class="sourceLineNo">165</span>// Internal methods<a name="line.165"></a>
<span class="sourceLineNo">166</span><a name="line.166"></a>
<span class="sourceLineNo">167</span>    private void checkState() {<a name="line.167"></a>
<span class="sourceLineNo">168</span>        if (this.closed)<a name="line.168"></a>
<span class="sourceLineNo">169</span>            throw this.kvdb.logException(new StaleTransactionException(this));<a name="line.169"></a>
<span class="sourceLineNo">170</span>        if (this.timeout == 0)<a name="line.170"></a>
<span class="sourceLineNo">171</span>            return;<a name="line.171"></a>
<span class="sourceLineNo">172</span>        final long time = (System.nanoTime() - this.startTime) / 1000000L;<a name="line.172"></a>
<span class="sourceLineNo">173</span>        if (time &gt;= this.timeout) {<a name="line.173"></a>
<span class="sourceLineNo">174</span>            throw this.kvdb.logException(new TransactionTimeoutException(this,<a name="line.174"></a>
<span class="sourceLineNo">175</span>              "transaction has timed out after " + time + "ms &gt; limit of " + this.timeout + "ms"));<a name="line.175"></a>
<span class="sourceLineNo">176</span>        }<a name="line.176"></a>
<span class="sourceLineNo">177</span>    }<a name="line.177"></a>
<span class="sourceLineNo">178</span>}<a name="line.178"></a>
<span class="sourceLineNo">179</span><a name="line.179"></a>




























































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